Tube for determining dissolved oxygen in low concentrations



March 22, 1960 s, BUCHOFF 2,929,687

TUBE FOR DETERMINING DISSOLVED OXYGEN IN LOW CONCENTRATIONS Filed May 12, 1954 INVENTOR.

LEONARD S. BUCHOFF BY g 334% ATTORNEYS Patented Mar. 22

non DETERMIISIING DISSOLVED s In Low CONCENTRATIONS OXYGEN The invention described herein may be manufactured andused by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates generally to a multiple chamber container and more particularly to a two chamber container for mixing a chemical reagent with a water sample in the determination of the dissolved oxygen content of boiler feed water.

Generally, in' the determination of the concentration of dissolved oxygen in water a colorimetric test is used. In this type of test a chemical reagent is added to a sample of boiler feed water. Upon the reaction of the i'a'gent with the oxygen a .visible' color 'is produced, the intensity of which is an indication of the amount of dissolved oxygen present in the water test sample. ,In maki g a quantitative determination of the dissolved oxygen present in a sample of boiler feed water it is necessa th t he 9P3 ll f the shem e en an the water sample be accurately measured and also that no external contaminating air be present during the mixing process. Prior testing devices are susceptible to such contamination when the reagent is added to the test sample.

An object of this invention is to provide a container that can be used in the determination of oxygen in boiler feed water.

Another object of this invention is to provide a sampling container for mixing an oxygen-containing reagent with a sample of boiler feed water.

A further object of this invention is to provide a sampling tube for mixing a chemical reagent with the boiler feed water sample without allowing air to enter the sampling tube.

Another object of this invention is to provide a sampling tube having an optically clear top and bottom.

A still further object of this invention is to provide a means for mixing accurately measured quantities of a reagent and a water sample.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description.

Figure 1 is an elevation in cross section illustrating the device in accordance with the invention;

Figure 2 is a view showing the details of the vial; and

Figure 3 illustrates the tube inverted for mixing the Water sample with the reagent.

Referring now to Figure 1, the principal parts of the invention include an elongated main tube 11, a clear glass stopper 12, a clear glass vial or inner tube 13, with a glass ball 14. The main tube 11 embodies a cylindrical wall portion 15, a closed optically clear bottom 16, and an open flared top portion 17 preferably having a finished seat for a stopper. The tube may be fabricated from glass or other similarly transparent material.

2 The stopper 12 is illustrated in detail in Figure 1. It has a clear top surface 21, a clear bottom surface 22, and a tapered portion 23 that is ground to fit closely with the flared portion 17 of the main tube shown in Figure l. The stopper may be made of glass or other similarly transparent material.

Figure 2 illustrates in detail the construction of the vial or inner tube and the ball. The vial 13 embraces a straight portion 31, a closed bottom 32, and an open top .33 The inner surface of the open top 33 may be finished to form a seat to fit the contour of the ball 14. The .vial 13 is mounted on the inner surface of the wall portion 15 of tube 11 near the top of the tube and parallel to the tube. The vial 13 may be either cemented or fused to the inner wall portion 15 of the main tube 11. The capacity of the vial is in the order of 1 cubic centimeter of liquid content. Calibration of the vial may be made so that an exact quantity of liquid is in the vial when it is filled to the top and the ball is placed in position.

Figure 3 illustrates the sampling tube in an inverted or mixing position, allowing the ball to drop on the vial and the reagent to mix with the water test sample.

In operation the vial 13 is filled -to the top and the ball 14 is placed on the vial. The tube 11 is completely filled with boiler feed water to be tested, and the Water is allowed to overflow to flush out any reagent that may have overflowed the vial during filling and closing of the vial. The filling should be in a manner not to displace the ball 14 from its seat at the top of the vial 13; The glass stopper 12 is then inserted, displaced water running out. 1

When the tube 11 is inverted, preferably immediately after the stopper 12 is in place, the ball 14 will drop out of place causing the reagent in the vial 13 to mix with the water test sample in the main tube. The main tube 11 is then shaken so as to thoroughly mix the reagent with the water test sample. The sample in the main tube 11 is now ready for a color comparison test without removal of the stopper 12. The amount of oxygen dissolved in the test sample is determined either visually, by spectrometric means, or through the use of photo electric equipment. It is to be noted that the shading or intensity of color is, preferably, determined by viewing the sample lengthwise through the tube. Therefore it is necessary that the bottom of the tube as well as the top and bottom of the glass stopper have optically clear surfaces. In order to get accurately reproducable results it is necessary that no air be allowed to come in contact with the reagent or with the test sample of Water during the test period during which the liquids are mixed and the color observed.

A colorimetric test for boiler feed water in which this tube can be used is described and claimed in the copending patent application Serial No. 429,417, filed concurrently herewith, entitled Colorimetric Determination of Dissolved Oxygen in Low Concentration, and now abandoned, to which reference may be made for further disclosure.

In the particular embodiment shown, used in a test as described in said application, the capacity of the small vial was 0.8 cubic centimeter and the capacity of the large main tube was 60 cubic centimeters.

It will be obvious from the above description that the above device lends itself readily to colorimetric testing where it is essential that exposure to air will be prevented during the test. The above described apparatus permits both a rapid and an accurate method of testing or determining the quantity of dissolved oxygen in boiler feed water test samples.

Obviously, many modifications and variations of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims the invention may be i I 7 terial and a ball cover fitting the open end, said reagent container mounted within the. main tube and near the top of said main tube and having its outer wall adjacent to the inner-wall of said main tube and parallel with said main tube. V A

2. A colorimetric testing device for determiningthe dissolved oxygen content in boiler feed water comprising an optically clear colorless main tube havinga'cylindrical wall portion, aclosed bottom portion and a flared, open top portion; an optically clear colorless stopper having a tapered portion ground to form an air tight seal with the flared portion of said main tube; an inner container having a cylindrical portion, a closed bottom portion, an open top portion, a ball stopper, said inner tube mounted within said main tube having its outer wall in contact with the inner wall of the main tube and parallel with said main tube. a

3. A water sampling device comprising an optically clear, colorless main tube having a closed bottom portion and an open top portion, a removable stopper means fitted to form an airtight seal with said open top portion, a vial mounted within said outer container having a closed bottom portion andan open top portion, a glass ball fitted to form an airtight seal with said top portion and removable upon tilting said vial from a vertical position. I

4. In a testing device the combination comprising a transparent cylindrical body member closedat one end thereof and adapted to contain a quantity of waterto be tested substantially filling said body member, a transparent cap tightly received at the other end of said body member, said cap having plane upper and lower surfaces substantially parallel with the closed end of the cylindrical body member, and with'the'lower surface of the cap in contact withthe watercontained in the body member, a second cylindrical bodyreceived'withinsaid first inentioned body member and secured to aside wall thereof, said second body having a valve-means operable to open upon rotation of said device, and a chemical re- 7 agent within said second body.

5. In a device for testing a boiler feed water sample the combination comprising a transparent cylindrical body member 'closed at one end thereof, a transparent cap adapted to fit at the other end thereof, the respective ends forming windows for the passage of light therethrough, a second cylindrical body member of smaller diameter than said first mentioned body member and re ceived therein, said second cylindrical body secured to a side wall of said first body'membe'r and adaptedto'ireceive a chemical reagent, and a ball closing'the top' of said second cylindrical body and removable therefrom upon rotation of the device through a large arc of revolution.

References Cited the file of patent l UNITED STATES PATENTS 532,630 Baird Ian..l5, 1895 588,005. Pomfret Aug. 10, 1897 611,520 Smith Sept. 27, 1398 1,759,866 Raab .-May 27, 1930 2,233,1 0 Eisen Feb. 25, 1941 7 2,533,806 Holzapfel Dec. 12, 1950 

1. A WATER SAMPLE TESTING DEVICE COMPRISING AN OPTICALLY CLEAR, COLORLESS MAIN TUBE, HAVING A CYLINDRICAL WALL PORTION, A CLOSED BOTTOM AND A FLARED TOP PORTION WITH ON OPEN END, A GLASS STOPPER MADE FROM OPTICALLY CLEAR MATERIAL, A TAPERED SECTION GROUND FOR AN AIR TIGHT FIT WITH A FLARED PORTION OF SAID MAIN TUBE, A REAGENT CONTAINER COMPRISING AN OPEN ENDED TUBE OF CLEAR MATERIAL AND A BALL COVER FITTING THE OPEN END, SAID REAGENT CONTAINER MOUNTED WITHIN THE MAIN TUBE AND NEAR THE TOP OF SAID MAIN TUBE AND HAVING ITS OUTER WALL ADJACENT TO THE INNER WALL OF SAID MAIN TUBE AND PARALLEL WITH SAID MAIN TUBE. 